CN110323575B

CN110323575B - Dual-polarized strong-coupling ultra-wideband phased array antenna loaded by electromagnetic metamaterial

Info

Publication number: CN110323575B
Application number: CN201910386194.6A
Authority: CN
Inventors: 杨仕文; 王炳均; 张航宇; 陈益凯; 屈世伟; 胡俊
Original assignee: University of Electronic Science and Technology of China
Current assignee: University of Electronic Science and Technology of China
Priority date: 2019-05-09
Filing date: 2019-05-09
Publication date: 2020-07-28
Anticipated expiration: 2039-05-09
Also published as: CN110323575A

Abstract

The invention discloses a dual-polarized strong-coupling ultra-wideband phased array antenna loaded by an electromagnetic metamaterial, which comprises a strong-coupling folded dipole unit, a feed balun, a metamaterial wide-angle impedance matching layer, a microstrip gradient line and a reflection floor, wherein the feed balun is arranged on the folded dipole unit; the tail ends of the strongly coupled folded dipole units are grooved for convenient dual-polarization design. The dipole and the designed feed balun are integrated on the same dielectric substrate, the bottom of the dipole and the designed feed balun is vertically embedded in the reflection floor, the wide-angle impedance matching layer is arranged on the top of the strong-coupling dipole unit, the coaxial electric connection with the balun is completed through the bent microstrip gradient line below the wide-angle impedance matching layer, and the impedance matching effect is achieved at the same time. According to the invention, the dual-polarization characteristic is achieved by elaborately designing the tail ends of the dipoles, a strong coupling folded dipole form is introduced, and a novel wide-angle impedance matching layer structure is loaded, so that the physical characteristics of low profile and light weight and excellent radiation performances such as ultra wide band and low cross polarization are achieved.

Description

Dual-polarized strong-coupling ultra-wideband phased array antenna loaded by electromagnetic metamaterial

Technical Field

The invention belongs to the technical field of antenna engineering, and particularly relates to a dual-polarized ultra-wideband strong-coupling folded dipole phased array antenna loaded by a metamaterial wide-angle impedance matching layer.

Background

Phased array antenna technology has emerged as early as the late 20 th century 30 s, and its working principle is to control the beam by changing the feeding phase in the array antenna. Phased array antennas are widely used in the fields of radar, communication and electronic countermeasure due to their beam rapid change capability, multi-beam scanning capability, spatial signal power synthesis capability, and the like. The development of modern radar, electronic communication and other technologies and the emergence of high-speed platforms such as airplanes and missiles put higher demands on the detection distance of the radar, the rapid target tracking and identifying capabilities and the like. Conventional wideband phased arrays have difficulty meeting these requirements. Because of mutual coupling effect among array elements, the traditional phased array is limited in bandwidth, and a complex and bulky structure needs to be additionally designed to eliminate the effect, so that the radiation performance of the antenna is prevented from being influenced. Although the traditional ultra-wideband phased array is mature, the realization methods have the disadvantages of large equipment quantity, complex used technology, high manufacturing cost of the array and low debugging and maintenance benefits. Meanwhile, similar to the antennas in the form of the currently widely used tapered slot antenna (Vivaldi), although they have an ultra-wide operating band and relatively stable electrical performance, they face limitations such as poor cross-polarization characteristics and too high antenna profile, which are not favorable for further development of antenna installation and conformality.

Based on the advantages and disadvantages of the antenna, and considering the requirement of high integration of modern electronic technology and electronic system functions, it is very critical to research a phased array antenna with the characteristics of low profile, light weight, ultra wide band, wide angle scanning, low cross polarization and the like. In recent years, a form of antenna for enhancing coupling between array elements and utilizing the coupling, i.e., a strongly coupled antenna, has been developed. Through strong capacitive coupling among the cells, the antenna not only reduces the transverse and longitudinal dimensions of the cells, but also achieves the characteristic of wider bandwidth than the traditional broadband antenna. Therefore, the research on the novel antenna structure is carried out to obtain the technical index of the antenna with higher performance, and the method has very important practical engineering significance.

Disclosure of Invention

Aiming at the defects in the prior art, the dual-polarized ultra-wideband strong-coupling folded dipole phased-array antenna provided by the invention solves the problems of overlarge weight, higher section and poor isolation characteristic of the existing phased-array antenna.

In order to achieve the purpose of the invention, the invention adopts the technical scheme that: a dual-polarized strong-coupling ultra-wideband phased array antenna loaded by electromagnetic metamaterial comprises a strong-coupling folded dipole unit, a wide-angle impedance matching layer, a feed balun, a microstrip gradient line and a reflection floor; the high-coupling folded dipole and the feed balun are integrated on the same dielectric substrate, the impedance matching layer is arranged on the top of the opposite-expansion coupling dipole unit and is parallel to the reflection floor, and the microstrip gradual change line is connected with the feed balun and is parallel to the reflection floor.

Furthermore, the strongly coupled folded dipole unit and the feed balun comprise two different polarization directions, and are respectively printed on the antenna dielectric substrates which are arranged in a cross manner;

the antenna dielectric substrate group comprises a first antenna dielectric substrate polarized along the Y direction and a second antenna dielectric substrate polarized along the X direction, and integrated dipoles and feed baluns are printed on the first antenna dielectric substrate and the second antenna dielectric substrate, wherein the feed baluns have different structures on the front side and the back side of the substrates;

the first antenna dielectric substrate and the second antenna dielectric substrate are arranged in a crossed mode, the first antenna dielectric substrate is provided with a groove at the position below the tail end of the dipole, the second antenna dielectric substrate is provided with a groove at the position above the tail end of the dipole, and the mutual insertion of the two substrates is completed;

furthermore, a parasitic structure for reinforcing the strong coupling effect of the dipole is arranged at the intersection of the first antenna dielectric substrate and the second antenna dielectric substrate. The structure comprises a dielectric substrate and four triangular patches printed on the dielectric substrate, wherein the patches are divided into two groups to act on X polarization and Y polarization, and the patches and the folded dipole patches need to be ensured to be electrically connected;

furthermore, a plurality of elliptical metamaterial rings are uniformly printed on the upper surface of the wide-angle impedance matching layer, and each metamaterial ring is of a periodic opening ring structure.

Furthermore, the microstrip gradient lines have two different orientations according to different polarization directions, and the microstrip gradient lines and the reflective floor board are printed on the front surface and the back surface of the same medium substrate.

The invention has the beneficial effects that: the dual-polarized ultra-wideband strong-coupling folded dipole phased-array antenna provided by the invention adopts Marchand balun for feeding, and the arrangement mode of dual-polarized units is ingeniously designed by slotting on the antenna substrate, so that very high polarization purity is achieved; the novel parasitic structure loaded at the tail end of the dipole unit strengthens the coupling between the dipoles to a certain extent, and achieves the effect of expanding the frequency band; the lower part of the dual-polarization antenna carries out impedance transformation between the coaxial and balun through a microstrip gradual change line, and avoids enough space through different microstrip line directions to carry out dual-polarization design; the novel elliptical metamaterial wide-angle impedance matching layer adopted by the antenna replaces the original thick and heavy pure medium matching layer, so that the aims of reducing the weight of the antenna and simplifying the structure of the antenna are fulfilled; the antenna and the feed balun are integrally printed on the dielectric substrate, and the antenna is simple to process, flexible and convenient to assemble, light in overall weight and stable in structure.

Drawings

Fig. 1 is a schematic structural diagram of an electromagnetic metamaterial loaded dual-polarized strong coupling ultra-wideband phased array antenna unit provided by the invention.

Fig. 2 is a schematic structural diagram of a dipole and a connected balun folded along the Y polarization direction in the embodiment provided by the invention.

Fig. 3 is a top view of a parasitic structure at a dipole end intersection in an embodiment of the invention.

Fig. 4 is a schematic diagram of an elliptical ring-shaped metamaterial wide-angle impedance matching layer loaded in the embodiment of the invention.

Fig. 5 is a schematic diagram of a bottom microstrip transition line structure of an antenna according to an embodiment of the present invention.

Fig. 6 shows the standing wave scanning condition of 0-45 degrees on the E-plane and the H-plane of one port of the dual-polarized unit of fig. 1 in the embodiment provided by the invention.

Fig. 7 shows the case of 0-45 degree full-band cross polarization on the E-plane and H-plane of one port of the dual-polarized unit of fig. 1 in the embodiment provided by the present invention.

Fig. 8 shows the scanning patterns and cross polarization of 0 degree, 45 degree azimuth plane and elevation plane at 2GHz after the cells form an 8X8 area array in the embodiment of the invention.

Fig. 9 shows the scanning patterns and cross polarization of 0 degree, 45 degree azimuth plane and elevation plane at 1GHz after the cells form an 8X8 area array in the embodiment of the invention.

Fig. 10 shows the scanning patterns and cross polarization of 0 degree, 45 degree azimuth plane and elevation plane at 0.35GHz after the cells form an 8X8 area array in the embodiment of the present invention.

Wherein: 1. a strongly coupled folded dipole element; 2. a wide-angle impedance matching layer; 3. a feed balun; 4. a microstrip transition line; 5. a reflective floor; 101. a first antenna dielectric substrate; 102. a second antenna dielectric substrate; 103. a parasitic structure that reinforces the coupling; 104. dual-polarization slotting; 105. parasitic patches that enhance coupling along the X-polarization direction; 106. parasitic patches to enhance coupling along the Y polarization direction; 201. an elliptical metamaterial ring; 301. a balun feed portion; 302. a balun coupling section; 401. microstrip gradual change line along Y polarization direction; 402. the gradient line is micro-strip along the X polarization direction.

Detailed Description

The following description of the embodiments of the present invention is provided to facilitate the understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and it will be apparent to those skilled in the art that various changes may be made without departing from the spirit and scope of the invention as defined and defined in the appended claims, and all matters produced by the invention using the inventive concept are protected.

As shown in fig. 1, the dual-polarized strong coupling ultra wide band phased array antenna loaded by the electromagnetic metamaterial comprises a strong coupling folded dipole unit 1, a wide-angle impedance matching layer 2, a feed balun 3, a microstrip gradient line 4 and a reflection floor 5; the high-power-consumption broadband antenna is characterized in that the high-power-consumption broadband.

As shown in fig. 2 to 5, the strongly coupled folded dipole element 1 includes a first antenna dielectric substrate 101 acting in the Y polarization direction, a second antenna dielectric substrate 102 acting in the X polarization direction, and a parasitic structure 103 for reinforcing coupling. The tail ends of the first antenna dielectric substrate and the second antenna dielectric substrate are provided with dual-polarized slots 104, so that the dual-polarized antenna can be assembled conveniently. It is noted that the dipole patch of each element is not electrically connected to the next element in the array, and there is a gap between them to create a strong coupling effect that achieves broadband characteristics. A coupling-enhancing parasitic structure 103 is disposed below a portion where the first antenna dielectric substrate 101 and the second antenna dielectric substrate 102 intersect, and the structure includes a dielectric substrate, a parasitic patch 105 printed thereon for enhancing coupling in the X-polarization direction, and a parasitic patch 106 printed thereon for enhancing coupling in the Y-polarization direction. Two sets of patches need be connected with the dipole electricity respectively to improve the electric capacity component between the dipole unit, strengthen the coupling characteristic, satisfy the broadband demand of antenna.

Taking the first antenna dielectric substrate 101 as an example, the dipole patch is printed on the first antenna dielectric substrate and is integrated with the feeding balun 3 at the lower part. The feed balun is in the form of a Marchand balun which includes a balun feed portion 301 connected to the underlying microstrip transition 4, printed on the opposite side to the dipole, and a balun coupling portion 302 printed on the same side as the dipole. The balun realizes the matching of the feed end and the antenna end.

At the top of whole antenna, be provided with the wide angle impedance matching layer 2 that adopts novel oval metamaterial structure, its upper surface evenly prints has oval metamaterial ring 201 of a plurality of, every metamaterial ring 201 is oval periodic opening loop configuration, this oval metamaterial ring 201 structure is with thinner base plate and unique periodic structure, it is heavier to have overcome traditional wide angle impedance matching layer weight, add the actual problems such as easy leaving the gap of man-hour, the lightweight and the modularization of antenna have been realized.

A section of bent microstrip gradual change line 4 is arranged below the antenna and between the coaxial connector and the feed balun 3. Similarly, due to the difference of polarization directions, in order to avoid enough processing space, the microstrip transition line is divided into a microstrip transition line 401 along the Y polarization direction and a microstrip transition line 402 along the X polarization direction. Taking the microstrip gradual change line 401 along the Y polarization direction as an example, the microstrip line at one end in contact with the coaxial connector is wider, the representative impedance is smaller and is substantially equal to 50 ohms, and when the tail end of the gradual change line is in contact with the feed balun, the microstrip line is narrower and narrower, the representative impedance is larger and is substantially equal to 100 ohms. The bending design ensures that the actual length of the transformation line is very long, and the stability of transformation is ensured. The round angle is poured out at the bending part of the microstrip line, and discontinuity in conversion is avoided.

In the structure, the antenna dielectric substrate, the balun dielectric substrate, the coupling-enhancing parasitic structure, the wide-angle impedance matching layer and the microstrip gradual-change line substrate are all Taconic-T L Y with the dielectric constant of 2.2, wherein the other side of the microstrip gradual-change line substrate is completely covered with metal, and the microstrip gradual-change line substrate is used as a floor of a microstrip bent line and a reflection floor of the whole antenna.

It should be noted that if the pitch of the array elements of the high frequency device is equal to half the wavelength of the highest frequency, any angle (except ± 90 degrees) can be scanned in the whole operating frequency band, and no grating lobe is generated. In order to ensure the antenna performance as much as possible, the radiation aperture of the antenna is not reduced so as to achieve higher gain. Therefore, the whole height of the phased array antenna is 0.45 high-frequency wavelength, and the distance between the adjacent dipole units is 0.45 wavelength at the highest frequency of the corresponding frequency band.

Fig. 6 shows the port corresponding standing wave characteristics of the embodiment in different scanning states of the E-plane and the H-plane, and it can be seen from the graph that the dual-layer dielectric substrate pair dipole ultra wide band phased array has an impedance bandwidth close to 7:1 in a 45-degree scanning range under the condition that the standing wave ratio requirement is less than 3.2. (since the two ports of the dual-polarized antenna are completely symmetrical in structure, the following figures show only one of the ports)

Fig. 7 shows the cross-polarization characteristics corresponding to all frequencies of the port in different scanning states of the E-plane and the H-plane in this embodiment, and it can be seen from the figure that the cross-polarization performance of the antenna in the whole operating frequency band can be below-30 dB, which is better than that of most strongly coupled antennas.

Fig. 8 shows the main polarization and cross polarization of the 8X8 area array provided by this embodiment under the condition of 0-degree and 45-degree scanning at the frequency point of 2 GHz. As can be seen from the figure, the double-layer dielectric substrate has the cross polarization characteristic of more than 30dB to the topological dipole ultra wide band phased array, the main polarization of the array can reach 22dB, and the main-to-side lobe ratio can reach more than 13 dB.

Fig. 9 shows the main polarization and cross polarization of the 8X8 area array provided by this embodiment under the condition of 0-degree and 45-degree scanning at the frequency point of 1 GHz. As can be seen from the figure, the double-layer dielectric substrate of the embodiment has a cross polarization characteristic of more than 35dB for the dipole ultra-wideband phased array; and the main polarization gain of the array can reach 20dB, and the main-side lobe ratio can reach more than 13 dB.

Fig. 10 shows the main polarization and cross polarization of the 8X8 area array provided in this embodiment under the condition of 0-degree and 45-degree scanning at the frequency point of 0.35 GHz; also has good cross polarization characteristic and beam scanning characteristic.

Claims

1. The dual-polarized strong-coupling ultra-wideband phased array antenna loaded by the electromagnetic metamaterial is characterized by comprising strong-coupling folded dipole units (1) which are arranged in a crossed mode, a wide-angle impedance matching layer (2), a feed balun (3), a microstrip gradient line (4) and a reflection floor (5); the strong coupling folded dipole unit (1) and the feed balun (3) comprise two different polarization directions and are respectively printed on antenna dielectric substrates which are arranged in a cross mode, each antenna dielectric substrate comprises a first antenna dielectric substrate (101) polarized along the Y direction and a second antenna dielectric substrate (102) polarized along the X direction, an integrated dipole and feed balun are printed on the antenna dielectric substrates, the lower part of the antenna dielectric substrates is connected with a coaxial connector through two micro-strip gradual change lines (4) in different directions for feeding, and the bottom of the antenna dielectric substrates is vertically embedded in a reflection floor (5); the impedance matching layer (2) is arranged at the top of the strong coupling folded dipole unit (1), elliptical metamaterial rings (201) are uniformly printed on the upper surface of a substrate of the matching layer, the structure is an open elliptical ring structure, the centers of the elliptical metamaterial rings are symmetrical and are periodically arranged, and each elliptical metamaterial ring unit is in one-to-one correspondence with the strong coupling folded dipole unit (1) by taking the intersection of the crossed strong coupling folded dipole units as the center but is not in direct contact with the strong coupling folded dipole unit; the microstrip gradient line (4) is connected with the feed balun (3) and is parallel to the reflecting floor (5).

2. The electromagnetic metamaterial-loaded dual-polarized strongly-coupled ultra-wideband phased array antenna as claimed in claim 1, further characterized in that a parasitic structure (103) for reinforcing coupling is arranged at the intersection of the first antenna dielectric substrate (101) and the second antenna dielectric substrate (102); the parasitic structure comprises a dielectric substrate and four triangular patches printed on the dielectric substrate, wherein the triangular patches are not in contact with each other and are divided into two groups to be respectively acted on X polarization and Y polarization, and the patches and the folded dipole patches need to be guaranteed to be electrically connected.